US3669775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of boron and phosphorous-containing glasses from silicon surfaces
Assignee: AT&T Inc
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Filing: 1969-12-29
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Granted: 1972-06-13
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Expires: 1989-12-29
Abstract
Abstract BORON AND PHOSPHOROUS-DOPED GLASSES WHICH ARE FORMED ON SILICON SURFACES DURING ELECTRONIC DEVICE MANUFACTURE MAY BE CHEMICALLY REMOVED BY A METHOD INCLUDING THE STEPS OF TREATMENT WITH A SOLUTION OF A SUITABLE CHELATING AGENT HAVING A PH OF AT LEAST 9.0 AT ROOM TEMPERAURE AND A TEMPERATURE OF A LEAST 85*C., FOLLOWED BY TREATMENT WITH AN OXIDIZING AGENT, FOLLOWED BY REPEATED TREATMENT WITH THE CHELATING AGENT SOLUTION.
Inventors
- 👤 Roy A Porter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:05
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |